Controlled liquid dispensing system



Aug, Z0, 1957 w. L. BEWLEY ET A1. 2,803,379

CONTROLLED LIQUID DISPENSYING SYSTEM .Filed Oct. 24, 1955 75 Mavim/feu /az y! Unite States atent ice conirnorsann Lioran nrsrnNsntG SYSTEM Wiiliarn L. Bewiey and Robert L. Switzer, Long Beach, Caif., assignors toUnion il Company of California, Los Angeles, Calif., a corporation of Caiiiornia Application ctober 24, 1955, Serial No. 542,207

Claims. (Cl. 222-20) This invention relates to the dispensing of liquids and particularly to an apparatus for the controlled dispensing of liquids at high volumetric rates in combination with simultaneous vapor recovery.

More specically the present invention relates to an improved process and apparatus for the transfer of vola- L tile liquids having relatively low boiling points, such as gasoline and light solvents as in the lling of vessels at very high rates wherein relatively large quantities of vapor are generated or displaced from the vessel.

Light, low boiling liquids present problems from air pollution and fire explosion hazard standpoints during the transfer thereof from one vessel to another. Such liquids comprise solvents including the low molecular weight alcohols, ketones, and esters, and including the light hydrocarbon solvents such as naphtha, and the relatively low boiling internal combustion engine fuels such as gasoline. These liquids have relatively high vapor pressures under normal temperature condition and evaporate very readily, especially during agitation. The vapoi-ization occurs `at substantial rates from vessels open to the atmosphere and occurs at considerably higher rates when the liquid is in motion such as during the introduction of liquid into the vessel. Exceedingly high rates of vaporization occur when the liquid is introduced into the vessel under conditions which cause it to splash either against the bottom or walls of the vessel or against the liquid level therein.

Under these conditions of liquid transfer where vaporization takes place, serious hazards due to possibility of re and/ or explosion, fume generation, and air pollution present themselves. Furthermore, these light solvents are frequently very expensive and any vaporization loss is expensive and wasteful of materials. Often local regulations govern the type and amount of such vaporized materials which can be handled in the open air in order to minimize the possibility of air pollution or the damage from fire or explosion.

One particular illustrative application of this invention, which is not to be considered as limiting the invention, is in the loading of gasoline tank trucks and trailers at high volumetric rates. These trucks and trailers have liquid capacities of as high as about 4,000 to 8,000 gallons and will load at rates as high as 1500 to 2000 gallons per minute. in the case of railroad tank cars, these capacities are of the order of 30,000 to 50,000 gallons and the loading rates may be increased if desired to as high as 2000 to 4000 gallons per minute. The quantity of displaced vapor laden air evolved from such operations is at least equal to and frequently greater than the volume of the vessel because of the agitation induced vaporization. it has been found that gasoline losses may range as high as about 35,000 gallons per month at an active gasoline loading station in which about 24 million gallons per month are handled, This amounts to a 0.15% volumetric liquid loss and is economically undesirable as well as involving a re hazard.

Coupled with the vapor recovery problem is the problem of controlling the flow rate of liquid when the ow rate is very high. Particularly the problem of hammering is difficult to avoid in those cases where vessels are being filled under circumstances wherein the operator is unable to detect the position of the liquid level within the tank visually as is the case when the operators vision through the loading hatch is necessarily obstructed by the presence of vapor recovery equipment. A further problem in automatic shut off systems lies in insuring a constant ilow rate during the shut olf so that a definite metered amount of lluid will be delivered during the valve closure. Still further, ebullition of liquid caused by filling at high rates can constitute a spillage and tire hazard when the tank is nearly full.

Accordingly the present invention is directed to an improved apparatus for the transfer of volatile liquids at very high flow rates which incorporates an eflicient mechanism for recovering the displaced or generated vapors and which includes a specic mechanism for termininating the flow after a preset volume has been delivered. This control apparatus includes a specially designed device which operates the main ilow control valve so as to reduce the ow from the maximum loading rate to a value between about 10% and about 50% during the period at which the last few gallons of the preset volume of liquid are delivered. This simultaneously permits accurate dispensing of the liquid, complete and safe recovery of often hazardous vapors, and the avoidance of the hammering and ebullition phenomena which are manifested when the rapid ilow of liquid is terminated.

It is a primary object of this invention to provide an improved apparatus for the controlled dispensing of volatile liquids which permits vapor recovery, accurate volumetric dispensing, and controlled termination of high rate liquid ows.

It is a more speciiic invention to provide in a segmented tubular loading arm a pneumatic control system which serves to deliver a preset volume of volatile liquid while recovering evolved or generated vapors and for the gradual and automatic reduction in flow rate during the period just prior to the completion of delivery of the desired volume.

It is a more specific object of this invention to provide a pneumatically operated control device including a pneumatic cylinder provided with a specially designed vent system intermediate the ends thereof which permits the pneumatic piston to throttle at an intermediate position and to control mechanical equipment such as liquid flow control valves at a partly open position.

Other objects and advantages of this invention will become apparent to those skilled in the art as the description thereof proceeds.

Briey, the present invention comprises an improved apparatus for the transfer of volatile liquids at high rates and incorporates means for receiving and preventing the loss of displaced gases, such as air, which are laden with evolved vapors of the liquid being handled. The apparatus comprises a jointed tubular loading arm provided with tubular swivels between each section. The loading arm consists of three essential conduit or pipe sections. These include a iirst section which is movable in a horizontal plane and is connected at its upstream end through an elbow and a vertical swivel to a source of liquid to be loaded, a second or intermediate section connected at its upstream end by means of a pair of elbows and a horizontal and a vertical swivel to the downstream end of the first section whereby the second section is movable in vertical planes at any angle to the irst section, and a third or vertical section connected by means of an elbow and a horizontal swivel t'o the downstream end of the second section.

The designation of swivels as being horizontal or A novel mechanical means is provided in conjunctionA with the second'and third conduit sections Ywhereby the third section, constituting the delivery end of the loading arm,is maintained at all times parallel to a given axis. In the loading of gasoline tank trucks for example having hatches which open through their upper surfaces, this mechanical means is adjusted to maintain the third section in a vertical position at all times regardless of the movements of the first and second sections. This vertical positioning is effected by yconnecting the second and third conduit sections to a longr rod which is parallel to and below the second section, and to a short vertical lever Ywhich extends down from the downstream end of the first conduit section so as'to form a parallelogram. All four connections are pivoted except that between the vertical lever and the iirst conduit section.

The third section is provided with an integrally atytached vapor collecting cap or hood which is adapted to seal against the inner edge of the loading hatch and prevent the direct escape therethrough of the vapors displaced when liquid is introduced into the vessel through the serially connected conduit sections of the loading arm. A exible conduit opens from the cap or hood and extends back along the segmented tubular loading arm whereby the displaced vapors are carried from the loading site. The maintenance of the third conduit section in a vertical position by the means above indicated is exceedingly important as it permits maintenance of this vaportight seal in spite of the settling of the tank truck or car during loading and which normally causes misalignment of the seal.

The equipment briefly described above is physically supported through a rigid connection at the upstream end of the iirst conduit section and is usually operated in conjunction with a loading rack consisting essentially of elevated horizontal walkway or platform which extend along the side of the truck loading driveway at a height of about 8 to l2 feet. The truck and trailer are positioned on the driveway parallel to the loading platform, the hatches are opened, and the loading arm is swung out over the truck. The third section is extended downwardly into each hatchway, and the vapor recovery head is seated in and sealed against the hatch. The introduction of liquid is begun and the displaced vapors ow upwardly through the hatch, into the vaporrcollecting head which prevents their escape to the atmosphere, and then through the exible vapor conduit to a suitable recovery system of the general types outlined below.

The usual liquid storage or transportation vessels, herein exemplified by gasoline trucks and trailers specifically, are not designed to withstand high operating pressures. The usual maximum pressure for these particular vessels is about 4.0 p. s. i. g. (pounds per square inch gauge). To prevent the buildup of undue pressures within the vessels being loaded, a novel apparatus is provided for automatically relieving any excess pressure during the loading and for fixing a desired maximum vessel pressure which cannot be exceeded. y

The second and third conduit sections of the loading arm are supported from the downstream end of the rst conduit section and are varied in position by means of a pneumatic cylinder which serves to raise and lower these sections of the arm. The pressure of air maintained on each side of the piston within this pneumatic cylinder is selected from a consideration of the weight of these loading arm sections, the area of the tank loading hatch, the maximum tank pressure, and the area of the piston in the pneumatic cylinder so as to maintain a predetermined downwardly acting weight of the second and third arm sections against the vessel hatch. This net downward weight is controlled, by controlling the cylinder air pressures as described, so that the net downward weight in pounds divided bythe area of the hatch opening in square inches does not exceed the maximum allowable pressure in pounds per square inchlof the vessel being loaded. For gasoline tank trucks as stated above this pressure is usually about 4.0 p. s. i. g. In such a truck having a l0- inch diameter hatchway the open area of the hatch is 78.5 square inches. The pneumatic cylinder is therefore loaded so as to leave a net downward weight of the loading arm of no greater than 314 pounds exerted through the vapor collecting head and against the vessel Vhatchway. In the event of a pressure build-up to 4.0 p. s. i. g. within the vessel, a force of 314 pounds is exerted through the vapor collecting head upwardly against the loading arm causing it to lift. This opens the hatchway to the atmosphere, permits vapors to escape from the vessel, and prevents the pressure from raising to a value greater than the allowable limit. In actualoperation with gasoline trucks, this net downward weight is preferably adg'usted to about 200 pounds whereby a Vessel buildup in pressure to 2.5 lp. s. i. g. will lift the vapor collecting head from the hatchway and provide a safety factor with respect to any pressure build-up.

This control of the net weight at the outer or downstream end of the loading arm is controlled within narrow limits by controlling the air pressure which exists within the pneumatic cylinder on each side or both sides of the piston. The upper end of the cylinder is attached to a vertical stanchion or davit which in turn is supported from the downstream end of the rst conduit section.

The piston is connected through a piston rod by means of a pivot to the second conduit section so that by increasing the air pressure on the lower side of the cylinder causes the second and third sections to be lifted. Obviously releasing this pressure will permit gravity to move the second and third section downwardly so as to set the vapor recovery head against the truck hatch. By maintaining a predetermined air pressure at all times in the lower part of the pneumatic cylinder with heavy loading arms, all but the desired net weight may be suspended by means of the cylinder. With lighter loading arms, as in the following example, a residual pressure is maintained above the piston to x the desired net downwardly acting force. In these ways the vapor relief valve provision is obtained.

The loading arm briefly described above is provided with a main control and shut-oi valve disposed adjacent the downstream end of the second conduit section. This valve may be manually operated and is provided with a valve positioner comprising a novel pneumatic or air cylinder which is connected into the control system hereinafter more fully described. At one extreme position of the valve positioner piston the valve is wide open, and at the other extreme position this control valve is closed. The valve positioner cylinder is provided withran intermediate vent consisting of a series of close spaced small holes drilled through the cylinder wall along a helical path, with each hole being spaced along this helical path from the adjacent holes by a `distance of between about 1/2 and 5 hole diameters. The length of Vthe perforated section along the cylinder is always less than the length of the piston head seal so as to avoid airrby-passing around the piston through the holes and manifold. These holes or apertures are manifolded within a collecting ring f instrument or control air flow to the valve positioner air cylinder. The pilot valve in turn is actuated through a direct mechanical linkage to kan Velectrically driven preset counter. The electric motor driven counter is in turn electrically connected to the generator turned by the positive displacement meters by means of which the quantity of liquid delivered through the loading arm during any loading period is measured.

In operation of the present device, after the loading arm has been placed into position for liquid dispensing, the preset counter is adjusted to show the liquid volume to be delivered, the dead man valve is opened thereby ermitting the valve positioner to open the main liquid Icontrol valve to the wide open position. As ow continues the preset counter, electrically actuated by the positive displacement meter, continuously determines the degree to which the desired volume has been delivered. At a time when all but lOO gallons or so of this volume has been dispensed, the preset counter actuates the pilot valve which in turn actuates the air cylinder valve positioner so as to reduce the delivery rate by partially closing the main control valve. This automatic reduction in delivery rate reduces the liquid velocity in the loading arm to a value such that it may be completely shut on? by closing of the main control valve without undue build-up of liquid pressures upstream from the valve due to liquid momentum within the loading arm. lt has been found that with gasoline loading for example at rates approximating 1200 gallons per minute, complete elimination of hammering is obtained when this preliminary reduction is from 1200 gallons per minute full flow rate to a value of about 400 to 500 gallons per minute for a period of about 5 to 15 seconds before complete shut-olf.

The apparatus briey described above will be more readily understood by reference to the accompanying drawings in which:

Figure l is an isometric view showing schematically the segmented loading arm to which the improved control equipment has been added according to this invention;

Figure 2 is a combination instrumentation drawing showing the pilot valve, the dead man valve, and the air cylinder valve positioner in vertical cross section, the pilot valve and valve positioner being shown in the full liquid ow positions;

Figures 3 and 4 show the pilot valve and valve positioner cylinders in the throttling or low flow position; and

Figures 5 and 6 show the pilot valve and valve positioner air cylinders in the closed position.

Referring now more particularly to Figure l the elements of the segmented tubular loading arm of this invention are shown. The description will be conducted in terms of the application of this device to the loading of volatile gasoline into tank trucks, but obviously the loading of other volatile liquids into any container is contemplated.

Gasoline from storage is pumped by means of a pump 11 through line 10 and into and through a positive displacement meter 12 wherein a total iiow during any given loading period is determined. Meter l2 rotates during liquid ow and drives an electric generator 13 which is connected by means of electrical connection 14 to an electric motor contained within electrically driven preset liquid volume counter 16 subsequently described. The liquid ows upwardly through check valve 18 and into rst conduit section 29 of the segmented loading arm. This is connected through a vertical swivel 22 so that the first conduit section may be moved in a horizontal plane.

The gasoline flow continues through tubular swivels 24 and 26 which connect the downstream end of irst conduit section to second conduit section 28. Because the two swivels 24 and 26 are separated by an elbow, second conduit section 2S may be positioned in any vertical or horizontal direction necessary. Mechanically attached to the upstream end of second conduit section 28 is an electrically driven preset counter 16 which is actuated by the positive displacement meter with respect to the amount of liquid pumped through the meters in relation to the preset volume to which the counter has been adjusted. The main control valve 30 is disposed adjacent the downstream end of second c011- duit section 23, and it is connected by means of two elbows and swivel 32 to third or vertical -conduit section 34 through which the gasoline is delivered to the tank truck. Vapor collector 36 provided with an external sealing surface 38 is supported on third conduit `section 34. Eispiaced vapors from the tank truck flow around third conduit section 34 upwardly into vapor collector 36 from which they are removed through a flexible con-` duit 38a. This flexible conduit is disposed along the lower side of the segmented loading arm and is connected through a spring loaded ycheck valve to suitable vapor recovery equipment. The latter may comprise a charcoal absorption system, a compression and condensation system, or a liquid absorption system which serves toA separate the volatile materials from the displaced air. Third section 34 is kept vertical regardless of the slope of second section 2S by vertical levers 25 and 27' pivoted to connecting rod 29 forming a parallelogram.

in Figure l the counter 16 is connected by a mechanical linkage 50 to pilot valve 42. This pilot valve is directly actuated by a counter 16 and serves to control the flow of instrument air through dead man valve 44- to the air cylinder valve positioner 46. The latter element is directly connected by linkage 48 to the control handle of the main control valve 30.

Dead man valve 44 is provided so as to interrupt the flow of air to valve positioner 46 and close the main control valve 36 in the event of casualty with respect to the loading operator, or if for any reason the operator leaves his post.

Valve positioner 46 is a specially designed air cylinder having intermediate vent ports which permit the cylinder to adjust the main control valve to a partially closed position so as to reduce the liquid low from the full ow rate in response to a signal generated by the preset counter l5 when all but a certain small quantity of the desired liquid volume has been delivered. ln this way the hammeringf ebullition, and the other problems of rapid liquid flow rate reductions are eliminated entirely.

The Vpreset counter 16, which serves to detect the delivery of a portion of preset volume of liquid and to activate the pilot valve in two steps when this desired quantity of liquid has been delivered, is an article of commerce. it is directly connected by means of linkage de to pilot valve 42. The pilot valve movements induced thereby and the valve positioner air cylinder 46 responses thereto are more clearly shown in Figures 2 through 6.

Referring now more particularly to Figure 2 cross sectional elevation views of pilot valve 42, dead man valve 44, and valve positioner air cylinder 46 are shown. Linkage 4t? together with a manual operator Sl are shown connecting the preset counter 16, not shown, with the pilot valve 4Z. The pilot valve is provided with a movable member 52 which serves to connect vent line 54 and air inlet line S6 with control ports 53 and 6l) which are connected to the valve positioner by means of iirst and second control conduits 59 and 61.

Valve positioner air cylinder 46 is provided with piston 62, piston rod 64, manual operator 66, a loading spring 63, and control ports and 72. This valve positioner is a conventional air cylinder modified to provide the intermediate venting port 74 shown. Around the periphery of the cylinder barrel is drilled a series of apertures 76. These apertures are spaced apart from one another between about 0.5 and about 5 aperture diameters and extend around the periphery of the barrel in a helical path whose longitudinal or axial length is less than the length of piston head 62 so as to avoid control air by-passing around the piston head to vent port 72. All

.of these apertures open into fluid manifold annulus78 contained within collecting ring 80, from which outlet or intermediate port 74 opens.

The pilot valve 42, the valve positioner 46, and dead man valve 44 are shown in Figure 2 in their wide open or full flow positions. In this position instrument air enters pilot valve 42 through port 56 and passes through channel S2 in the valve, through port 58 and rst control conduit 59 through channel 84in dead man valve 44 so long as the handle 86 thereof is manually depressed. This air continues into valve positioner 46 through port 70 and forces piston 62 into the position shown and keeps the main control valve 30, outlined by dotted lines, in a wide open position. In the event the dead man valve is released, spring loaded handle 86 rises isolating pilot valve 42 from valve positioner 46, the instrument air owing from port 58 being cut-off, and air from port 70 of positioner 46 is vented through channel 8S through vent line 90. With the supply of instrument air cut ot and port 70 vented, the loading spring 68 throws control valve 30 into the closed position, as indicated in Figure 6.

ln the wide open or full ow position shown in Figure 2, the pilot valve is in a position so that inlet port 56 is open and connected to control port 58 while control port 6% and vent port 54 are sealed.

When all but the small remaining portion of the predetermined volume of liquid has been delivered, the preset counter i6 reacts through linkage 40 and moves the pilot valve 42 from the position shown in Figure 2 into the position shown in Figure 3 in which inlet port S6 remains connected through channel 82 to control port S8, but in which control port 60 is now opened and connected to Vent port 54. With this change, the instrument air supplied continues from port 56 through port 58 into port 70 of valve positioner 46 shown in Figure 4, but since intermediate port 74 of the valve positioner is now connected through port 60 to vent line 54, the instrument air is permitted to leak through at least some of the apertures 76 previously described. How through the small apertures generates a pressure drop and permits loading spring 68 to move piston 62 to an intermediate position covering some of the apertures 76. The actual intermediate position is determined by the tension of loading spring 63 in relation to the pressure of the instrument air supplied through port 56.

By bringing piston 62 to the intermediate position shown the main control valve 30 is thus partially closed to reduce the liquid ow rate to the desired value for a short period before it is thrown into the completely closed position.

Shortly following this first impulse from the preset counter 16 and during which time the completion of delivery of the volume of liquid desired occurs, a second signal from the counter throws the pilot valve into the position shown in Figure 5. Here inlet air port 56 is sealed and both control ports SS and 60 are connected through channel 92 to vent port 54. Because of the connections of control ports 58 and 60 to ports 70 and 74 of valve positioner 46, this position of the pilot valve prevents` any flow of instrument air and vents any high pressure air from cylinder 46 through ports 70 and 74. With no high pressure instrument air present in valve positioner 46, piston 62 is returned by means of loading spring 68 to the position indicated in Figure 6, which completely closes main control valve 39 and terminates the liquid delivery.

As indicated briefly above the position of piston 62 in the valve positioner air cylinder and therefore the degree to which the main control valve is closed is determined by the adjustment of loading spring 68 and the pressure of the instrurnent air supplied through inlet port 56. It is also to some extent determined by the longitudinal distance of the perforated central section in the valve positioner air cylinder barrel. By means of the load- Thisv ing spring adjustment and the inlet air pressure the degree of reduction in liquid flow during the last stage of liquid delivery. may be determined. It has been found preferable to reduce the flow rate at least to below the 50% point and prferably to a value between about 10% and about 30% of the maximum flow rate in order to avoid-hammering eiects during ow termination.

Although the .centrally perforated valve positioner air cylinder shown and described above has been found to be highly suited to the service herein described it is not intended thaty this device be limited to these uses. There are many applications in which valve positioning is required and of course this valve positioner consisting of Van air cylinder with an intermediate perforate section surrounded by a sealed collector ring may be employed. Such services are well known to those skilled in the art. The use of this device is of course not necessarily restricted to positioning valve elements, but can be used in the adjustment of other mechanical devices wherein an intermediate position is desirable between two extreme positions.

The present invention was applied in the'preset volumetric metering of automotive gasoline in Los Angeles, California at a loading station in which approximately 24 million gallons of gasoline per month were loaded into tank trucks. The loading arms were fabricated of 4inch diameter conduit, each of the lirst and second conduit sections being approximately 5 feet in length. The loading rates through these devices were held at about 1200 gallons per minute and the vapors displaced from tank trucks were collected and conducted from the loading site. The pilot valves employed in this device were as illustrated in Figures 2, 3, and 5 and were directly actuated by the electrically driven preset counter described above. The pilot valve operated in conjunction with a dead man valve as indicated in Figure 2 which controlled the ow of instrument air to the air cylinder valve positioner shown in Figures 2, 4, and 6. This air cylinder had a Z-inch bore and a 6-inch stroke, Was provided with a helical row of holes through the air cylinder barrel at an intermediate point along the length of the cylinder. These holes were drilled with a No. 50 wire drill and were spaced 1.5 hole diameters center-to-center apart from one another along a 45 helical path around the cylinder. The air cylinder piston was directly connected to the main flow control valve and was spring loaded to bias this valve into the normally closed position. f

Extensive testing of the above described device at the loading terminal indicated has proved it to be a highly successful and reliable control system.

A particular embodiment of the present invention has been hereinabove described in considerable detail by way of illustration. It should be understood that various other modilications and adaptations thereof may-be made by those skilled in this particular art without departing from the spirit and scope of the invention as set forth in the appended claims.

l. In an apparatus for transferring volatile liquids into a container and collecting evolved vapor therefrom without loss to the atmosphere which comprises .a segmented loading arm conduit including a first, a second, anda third conduit section serially connected by means of conduit swivels, said second and third conduit sections being adapted thereby to be raised ,and lowered, a vapor co1- lecting head surrounding said third conduit section and adapted to be sealed against the opening of said container, a flexible conduit for vapor opening from said head and extending back along said segmented loading arm, and a main flow control valve connected in said second conduit section, the improvement in combination therewith which comprises a pneumatic cylinder having a piston and piston rod disposed adjacent said control valve, said piston rod being connected so as to actuate said control valve, a loading spring biasing said piston into an extreme position in said cylinder at which said control valve is closed, said cylinder having a uid manifold disposed around an intermediate portion thereof which opens through at least one port into said cylinder, a preset counter connected to a meter which is actuated by the volume of liquid delivered through said loading arm, a pilot valve connected to and actuated by said preset counter, an inlet conduit for a control fluid under pressure opening into said pilot valve, a vent conduit opening therefrom, a iirst control conduit connecting said pilot valve to an end port of said cylinder, a second control conduit connecting said pilot valve to said iiuid manifold, and a vent port conduit opening from the other end port of said cylinder, said preset counter being adapted to actuate said pilot valve so as to supply air to said cylinder and open said control valve until all but a minor amount of a preset liquid volume has been delivered, then vent said intermediate port so as to permit said loading spring to bring said piston into an intermediate position adjacent said port so as to close partially said main control valve while said minor amount of liquid is delivered at a reduced rate, and then vent all cylinder ports to spring close said control valve.

2. An apparatus according to claim l in combination with a spring closing dead man valve connected in said iirst control conduit, said valve being manually operated to supply control fluid from said pilot valve to said air cylinder.

3. An apparatus according to claim 1 in combination with a positive displacement meter connected upstream from said segmented loading arm, an electric generator driven thereby, an electric motor which drives said preset counter, and an electrical connection between said motor and said generator.

4. An apparatus according to claim l wherein said manifold surrounds a plurality of apertures opening through the wall of said cylinder, said apertures being spaced apart from one another between about 0.5 and about 5.0 aperture diameters, the length of the thus perforated section of said cylinder being less than the length of the head seal on said piston.

5. An apparatus according to claim 4 wherein said apertures are disposed along a helical path on the wall of said cylinder.

6. An apparatus for transferring a predetermined volume of liquid at a high flow rate into a container without adverse effects of ebullition and line hammering which comprises, in combination with a delivery conduit opening from a source of liquid into a container to be filled, a pump in said conduit, a liquid delivery meter in said conduit, a spring-loaded normally closed ow control valve in said conduit, a valve positioner cylinder disposed adjacent said valve and provided with a piston and a piston rod connected to actuate said valve, a fluid manifold surrounding and communicating with said positioner cylinder at an intermediate point, a preset liquid volume counter connected to and actuated by said liquid delivery meter, a pilot valve directly actuated by said counter so as to be retained in a full flow position until all but a minor part of the preset volume of liquid has been delivered, then be moved into a throttled flow position during delivery of said minor part, and then be moved into a closed position, a first and a second control conduit connecting said pilot valve to said positioner cylinder, a vent conduit opening from and a supply conduit into said pilot valve for control fluid under pressure, said full flow position of said pilot valve being one in which the control uid is supplied therethrough to move said piston against the spring load to an extreme position at which said control valve is wide open and in which said manifold is sealed, said throttled iow position being one in which the control fluid is supplied as in the full ow position and in which said manifold is vented whereby said piston rests at equilibrium between the control uid force and the spring load force at an intermediate position in said cylinder with said control valve partially closed, and said closed position being one in which said supply conduit is sealed and said control conduits are vented to permit said loading spring to close said control valve completely.

7. An apparatus according to claim 6 in combination with a spring-loaded normally closed and vented dead man valve connected in one of said control conduits between said pilot valve and said positioner cylinder whereby manual actuation thereof is required to supply control fluid to said positioner cylinder.

8. A valve positioner apparatus which comprises in combination with a control valve to be operated, a pilot valve having an inlet port for control fluid and a vent port and a rst and second control port, a pneumatic cylinder having two end ports and disposed adjacent Said control valve, a piston disposed within said cylinder and sealed against the cylinder walls, a piston rod connecting said piston with said control valve, a spring biasing said piston toward one end of said pneumatic cylinder, a rst control conduit connecting said first control port with one end port, a second control conduit connecting said second control port with a manifold, said manifold surrounding said cylinder at an intermediate position and enclosing at least one opening through the wall thereof, a vent conduit from the other end port of said cylinder, said pilot valve adapted to seal said second control conduit and supply control uid via said first control conduit to move said piston against said spring to one extreme position at which said control valve is open, and adapted to vent said second control conduit so as to permit said spring to move said piston to an intermediate point adjacent said manifold to close said control valve partially, and to vent both control conduits so as to permit said spring to move said piston to the other extreme position at which said control valve is closed.

9. An apparatus according to claim 8 in combination with a spring-loaded manually operated three-way venting dead man valve connected in said rst control conduit, said pneumatic cylinder being vented through said dead man valve and isolated from `said pilot valve except when said dead man valve is manually actuated.

10. An apparatus according to claim 8 wherein said manifold encloses a plurality of apertures through the cylinder wall, said apertures being disposed along a helical path having a longitudinal extent which is less than the sealed length of the piston.

References Cited in the iile of this patent UNETED STATES PATENTS 542,628 Clark July 16, 1895 1,047,146 Balloco Dec. 17, 1912 1,495,058 Wille May 20, 1924 2,086,853 Highsmith Oct. 26, 1937 

1. IN AN APPARATUS FOR TRANSFERRING VOLATILE LIQUIDS INTO A CONTAINER AND COLLECTING EVOLVED VAPOR THEREFROM WITHOUT LOSS TO THE ATMOSPHERE WHICH COMPRISES A SEGMENTED LOADING ARM CONDUIT INCLUDING A FIST, A SECOND, AND A THIRD CONDUIT SECTION SERIALLY CONNECTED BY MEANS OF CONDUIT SWIVELS, SAID SECOND AND THIRD CONDUIT SECTIONS BEING ADAPTED THEREBY TO BE RAISED AND LOWERED, A VAPOR COLLECTING HEAD SURROUNDING SAID THIRD CONDUIT SECTION AND ADAPTED TO BE SEALED AGAINST OPENING OF SAID CINTAINER, A FLEXIBLE CONDUIT FOR VAPOR OPENING FROM SAID HEAD AND EXTENDING BACK ALONG SAID SEGMENTED LOADING ARM, AND A MAIN FLOW CONTROL VALVE CONNECTED IN SAID SECOND CONDUIT SECTION, THE IMPROVEMENT IN COMBINATION THEREWITH WHICH COMPRISES A PNEUMATIC CYLINDER HAVING A PISTON AND PISTON ROD DISPOSED ADJACENT SAID CONTROL VALVE, SAID PISTON ROD BEING CONNECTED SO AS TO ACTUATE SAID CONTROL VALVE, A LOADING SPRING BIASING SAID PISTON INTO AN EXTREME POSITION IN SAID CYLINDER AT WHICH SAID CONTROL VALVE IS CLOSED, SAID CYLINDER HAVING A FLUID MANIFOLD DISPOSED, SAID INTERMEDIATE PORTION THEREOF WHICH OPENS THROUGH AT LEAST ONE PORT INTO SAID CYLINDER, A PRESET COUNTER CONNECTED TO A METER WHICH IS ACTUATED BY THE VOLUME OF LIQUID DE LIVERED THROUGH SAID LOADING ARM, A PILOT VALVE CONNECTED TO AND ACTUATED BY THE SAID PRESET COUNTER CONNECTED TO CONDUIT FOR A CONTROL FLUID UNDER PRESSURE OPENING INTO SAID PILOT VALVE, A VENT CONDUIT OPENING THEREFROM, A FIRST CONTROL CONDUIT CONNECTING SAID PILOT VALVE TO AN END PORT OF SAID CYLINDER, A SECOND CONTROL CONDUIT CONNECTING SAID PILOT VALVE TO SAID FLUID MANIFOLD, AND A VENT PORT CONDUIT OPENING FROM THE OTHER END PORT OF SAID CYLINDER, SAID PRESET COUNTER BEING ADAPTED TO ACTUATE SAID PILOT VALVE SO AS TO SUPPLY AIR TO SAID CYLINDER AND OPEN SAID CONTROL VALVE UNTIL ALL BUT A MINOR AMOUNT OF A PRESET LIQUID VOLUME HAS BEEN DELIVERED, THEN VENT SAID INTERMEDIATE PORT SO AS TO PERMIT SAID LOADING SPRING TO BRING SAID PISTON INTO AN INTERMEDIATE POSITION ADJACENT SAID PORT SO AS TO CLOSE PARTIALLY SAID MAIN CONTROL VALVE WHILE SAID MINOR AMOUNT OF LIQUID IS DELIVERED AT A REDUCED RATE, AND THEN VENT ALL CYLINDER PORTS TO SPRING CLOSE SAID CONTROL VALVE. 